Intestinal Adaptation to Diabetes Nutrient Chronically Diabetic Rats Richard

To examine the pattern and mechanism of enhanced intestinal nutrient absorption in diabetes, we measured intestinal transport of 3-0-methylglucose (30MG), I-alanine (ALA), and SO4 in male Lewis rats made diabetic with streptozocin. Diabetes enhanced 30MG absorption fivefold in ileum and threefold in jejunum; ALA absorption increased twofold in ileum but not at all in jejunum; ileal S04 transport was unaffected. Increases in 30MG and ALA transport were due solely to increases in maximum velocity. The enhancement of ileal glucose absorption waas half-maximal in 40-45 d, could be reversed by 10 d of treatment with insulin and did not result from adrenergic denervation. The density of glucose carriers per milligram brush border protein (measured as IHlphlorizin binding sites) was not altered but there was a sixfold increase in the number of glucose-inhibitable [1Hjphlorizin-binding sites in the intact epithelium. Generalized mucosal hypertrophy accounted for < 30% of this increase. We conclude that the intestine adapts to streptozocin-induced diabetes through recruitment of additional brush border carriers for sugar, probably in the midvillus-to-crypt region.